Low grade Iron Ore Beneficiation and the Process of Jigging Iron ore resources are getting consumed at an accelerated rate because of the growth in the production of iron and steel. Due to this reason the availability of high grade iron ore is reducing and the supply of high grade iron ore to iron and steel plants is declining sharply. Hence, the scenario is steadily shifting towards the use of low grade iron ores and slimes which are stock piled in the mine’s sites for years. These dumped slimes also, in fact, falls in the category of low grade iron ore. Also, some of the ores of iron have a complex mineralogical composition and do not respond to conventional beneficiation techniques. Modern beneficiation processes allow for effective and low cost upgrading of lump, fines and ultra-fines of such ores. Since the iron ores consist of several compositions, mineralogies, shapes, and sizes, so there is no ‘one size fits all’ approach to the beneficiation of iron ore. Most of the ‘run-of-mine’ (ROM) iron ore contain a large percentage of other materials which need to be removed through the process of beneficiation before the ore attains the specifications needed for its use. The extent of the beneficiation techniques employed depends on the level and nature of diluents and the form of distribution of the gangue and impurities in the ore structure. Liberation of ore is an essential step for making it responsive to the beneficiation techniques. For selection of appropriate techniques, it is necessary to carry out first the mineralogical assessment of the ore so as to get the insight into the ore and to know the gangue association, and grain size etc. There are several issues relating to categorization and beneficiation of low grade iron...

Comparison of Steel with Aluminum Steel is an alloy of iron and other elements, primarily carbon. It is most commonly produced by reduction of iron ore. Carbon, the most common alloying material in steel, acts as a hardening agent, preventing any dislocations within the iron atom crystal lattice from separating and sliding past each other thus making steel more durable. By varying the amount of alloying elements and the form of their presence in the steel, one can control qualities such as hardness, ductility, and tensile strength of steel. Though, steel has been known to be around since 4,000 years ago, it was not widely produced until the 17th century. Its mass production started due to the introduction of the Bessemer process during 1850s. This process made steel production cheaper, efficient and easier. Production of steel is a two stage process. First iron is produced by reduction of iron ore. This iron is then converted into steel by oxidizing the impurities. (Fig 1) Fig 1 Production process of steel Steel is widely used in construction and other applications because of its high tensile strength and low cost. Iron is the basic component of steel. Composition of steel mainly consists of iron and other elements such as carbon, manganese, silicon, phosphorus, sulphur, and alloying elements. A large number of elements in wide ranging percentages are used for the purpose of alloying of steels. Variations in chemical composition of steels are responsible for a great variety of steel grades and steel properties. Each element that is added to the basic steel composition has some effect on the properties of the steel and how that steel reacts to the processes of working and fabrication of steels. The chemical composition of steel also determines the behaviour of steel in...

Converter Gas, its Characteristics and Safety Requirements During the process of steel making in the basic oxygen furnace (BOF), significant amount of gases, rich in carbon monoxide content, are generated during the blow time at a temperature of 950 deg C. This gas is termed as converter gas or BOF gas. Converter gas is also known as LD gas. It is a byproduct gas produced during the production of liquid steel in a basic oxygen furnace (converter), where impurities of hot metal are oxidized with oxygen gas. The main constituents of converter gas are carbon mono oxide (CO), carbon di oxide (CO2), oxygen (O2) and nitrogen (N2). Composition wise it is similar to blast furnace gas but with lesser percentage of nitrogen in it. Converter gas is dust laden at the converter mouth. The dust content is around 100 to 120 g/N cum. The recovered converter gas is cleaned in a venturi scrubber using water, followed by processing in the mist eliminators. The gas is then stored in gas holder for steady supply and cleaned further in the electrostatic precipitators (ESP) and finally fed to the gas distribution system. Wet type of gas cleaning plants have capabilities to reduce the dust content of the gas to a level of 5 mg/N cum. The composition of the gas varies from start to the end of the blow and this is a function of the blow time. In the oxygen rich phase (air ratio= 1) at the beginning and at the end of the blowing period the primary gas is burned completely and no gas is recovered during this period. During CO rich phase (air ratio less than 1) only partial oxidation takes place and a combustible waste gas is formed containing CO, H2, CO2 and...